Hydrodynamic accelerator



July 18, 1967 A. KERMABON 3,331,453

HYDRODYNAMI C ACCELERATOR Filed Feb. 23, 1965 Fig.2.

Z/Vl/E/v TO 1?: HA/ME KER/V950 United States Patent 3,331,453HYDRODYNAMIC ACCELERATOR Andr Kermabon, 51 Via Della Vittoria, S.Tereuzo, La Spezia, Italy Filed Feb. 23, 1965, Ser. No. 434,711 3Claims. (Cl. 175-6) ABSTRACT OF THE DISCLOSURE The invention relates toan ocean floor sediment cover in which a linear tube, open at one endand provided with a transverse fracturable wall, includes an explosivecharge actuated by a magnetic switch. The charge breaks the wall andallows water to enter the tube to drive it into the sea bed byimplosion.

The object of this invention is tto provide a mechanical device which byuse of the external hydrostatic pressure permits a tube to beaccelerated at suificient marine depth. This accelerated tube, if fittedwith a penetration nose, may be used as a sediment corer.

The device is lowered down to the sea floor by means of a cable and thetube is recovered; the low cost castiron piston is eventually lost.

An embodiment of device in accordance with the invention is hereinafterparticularly described with reference to the accompanying drawings,wherein:

FIG. 1 is a diagrammatic side elevation of the tube and piston.

FIG. 2 is a side elevation of a practical embodiment.

FIG. 3 is a partial longitudinal section of a detail of an igniter forthe tube.

FIG. 4 is a partial cross section of a detail.

The device is light in weight and is essentially composed of a lightmetallic tube, a heavy piston, and a light cap.

A tube 1 is closed at one end by a cap 2, and at the other by a piston 3thereby retaining in the reservoir 4 a certain volume of partial vacuumor of air at atmospheric pressure.

The assembly of tube, cap and piston is submitted to the external forcescreated by the hydrostatic pressure statically counterbalanced by theinternal forces of the rigid mechanical assembly, until a release device5 frees the piston with respect to the tube. Then the tube 1 isaccelerated downward due to the vertical force applied to the cap 2, andthe piston 3, due to the pressure force applied to it, is acceleratedupward. If the mass of the piston is M and m the mass of the tube andthe cap, and if friction is neglected, one can write Mv=mV when v is theinstantaneous speed of the piston during the propulsion period and V isthe instantaneous speed of the tube and the cap.

During the propulsion period the piston 3 compresses the air stored inthe tube 1 until the pressure reaches the external ambient pressure. Thevertical internal forces are then equal to the vertical external forcesand the kinetic energy of the piston is suflicient to drive away thelight cap 2 of the tube. Then only the tube has a large downward finalvelocity while cap and piston travel upward at a lower speed.

The system can be reversed to accelerate downward a light piston. Thenthe tube has to be heavy, the cap remaining light.

If the tube is lOng enough the speed limit can be reached without theuse of a heavy piston and a simple diaphragm is sufficient.

The following is a description, given by way of example, of a deviceused as a sediment corer, see FIG. 2.

The corer is made of three lengths, 6, 7, 8 of light alloy tube ofinternal diameter 127 147 mm.

The tubes 7 and 8 are each six metres long and are connected by a longwatertight joint 9. The lower end of the tube 7 is closed by a glassdiaphragm 10' able to sustain great marine pressure.

The upper end of tube 8 is closed by a watertight cap 11. Tubes 7 and 8are used as reservoirs of energy, and air at atmospheric pressure isstored in them. Tube 6 is connected to the end of tube 7 by anoverlapped joint in which a cast iron piston 12 sides loosely (with aclearance of the order of mm. on the diameter).

At the lower end of tube 6 a nylon core catcher actuated by pressure isinstalled. Tube 6 is six metres long or less. The piston 12 is preventedfrom falling by means of a small shear pin which holds it in tube 6.

A tube 13 has directional fins. It is two metres high and has an insidediameter of 250 mm.

The corer is suspended by means of two wires 14, terminated by retainingrings. The rings are held in a release mechanism 15. The system isbalanced by a counterweight 16 suspended on a wire 17.

The wire 17 is approximately thirty metres in length. A retrieving wire18 is also thirty metres in length. A small wire 19 (diameter 2 mm.)connects the release mechanism 15 to an implosion igniter 20.

When mass 16 reaches the sea floor, the corer is freed by the releasemechanism 15, wire 19 is put under tension and cover 21 is withdrawn.Then the glass diaphragm 10 is broken. The implosion process is thenstarted.

Piston 12 starts moving upward and the tube assembly starts movingdownward at about the same speed if weight of tube assembly is equal tothe weight of the piston, i.e. each is kg. When air inside the tube iscompressed at ambient pressure the piston pushes ca 11 away. The pistonand the cap follow their course upward and are lost. Although, in thepresent system the piston is lost a simple mechanical system can bedevised to recover it. A slight slope on top of the piston deviates thecourse of the piston when it enters the water and this way any collisionbetween piston and release mechanism is avoided. The tube assembly thenpenetrates the sediments at high speed and the high kinetic energy givesa great penetration with a light equipment.

Supposing the system to be imploding at a depth of 2,500 m. and thepiston weighing half the total weight of the tube assembly, the energyavailable to accelerate the tube is about 1200K joules.

If the tube 6 is made long enough (about six metres) no piston is neededdue to the fact that the stored energy is quite large, and the waterchannelled in tube 1 acts as a piston at the beginning of the implosion.The total eficiency of the system is however slightly smaller.

The tube assembly is retrieved from sediments by the cable 18. Thefollowing describes the principle of the igniter, see FIG. 3.

The cover 21 attached to the release cable 19 is made of soft iron. Whenin place it surrounds a magnet 22 and this Way closes the magnetic fieldexisting. 23 is a magnetic switch which closes if submitted to anexternal magnetic field, This switch 23 is mounted in with a 12 v.battery 24 and an explosive charge 25. The charge is glued on glassdiaphragm 10.

When the corer 7 is retrieved the magnetic field of magnet 22 passesthrough the non-magnetic coring tube and switch 23 is closed. The chargethen explodes and the shockwave breaks glass diaphragm 10. The water canthen flow freely upward in tubes 7 and 8.

The shapes, dimensions, arrangement and material of the various parts ofthe system can be changed without mm. and external diameter altering thegeneral concept of the invention herewith described.

I claim:

1. A hydrodynamic accelerator comprising a linear tube open at bothends, a fracturable transverse wall disposed across the tube inward of afirst end of the tube, an explosive charge adjacent to said transversewall, an electrical circuit including a current source and amagnetically-operable switch disposed in the tube and connected to theexplosive charge, a magnet positioned externally on the tube adjacent tothe switch, a magnetic keeper removably positioned adjacent the magnet,means for removing the keeper from the magnet, and a closure for thesecond of the tube.

2. A hydrodynamic accelerator, as claimed in claim 1, in combinationwith a relatively massive piston positioned with clearance in the tubeexternally of the fracturable transverse wall.

3. In combination, for use as a deep-sea sediment coring device, ahydrodynamic accelerator as claimed in claim 1, a tubular supportinghead removably engaged on the second end of the tube, a suspension meansincluding a cable, a latching device by which the supporting head lisseparably connected to the suspension means, a probe depending from thelatching device for release of the latching device when the probecontacts and becomes supported by the sea bed, and a flexible connectorcoupling the suspension means for fracturing the transverse wall foroperating said fracturing means when the supporting head has becomeseparated from the suspension means.

References Cited UNITED STATES PATENTS 2,176,477 10/1939 Varney et a11756 2,664,269 12/1953 Knight et a1 175-254 X 3,118,417 1/1964 StanwiCk175--6 3,155,174 11/1964 Niskin 1756 X 3,170,433 2/1965 Gardiner114-206.1 FOREIGN PATENTS 1,370,539 7/1964 France.

20 CHARLES E. OCONNELL, Primary Examiner.

R. E. FAVREAU, Assistant Examiner.

1. A HYDRODYNAMIC ACCELERATOR COMPRISING A LINEAR TUBE OPEN AT BOTHENDS, A FRACTURABLE TRANSVERSE WALL DISPOSED ACROSS THE TUBE INWARD OF AFIRST END OF THE TUBE, AN EXPLOSIVE CHARGE ADJACENT TO SAID TRANSVERSEWALL, AN ELECTRICAL CIRCUIT INCLUDING A CURRENT SOURCE AND AMAGNETICALLY-OPERABLE SWITCH DISPOSED IN THE TUBE AND CONNECTED TO THEEXPLOSIVE CHARGE, A MAGNET POSITIONED EXTERNALLY ON THE TUBE ADJACENT TOTHE SWITCH, A MAGNETIC KEEPER REMOVABLY POSITIONED ADJACENT THE MAGNET,MEANS FOR REMOVING THE KEEPER FROM THE MAGNET, AND A CLOSURE FOR THESECOND OF THE TUBE.